2010

Rapid prototyping of polydimethylsiloxane(PDMS) is often used to build microfluidic devices. However, the inherent hydrophobic ture of the material limits the use of PDMS in many applications. While different methods have been developed to transform the hydrophobicPDMSsurface to a hydrophilicsurface, the actual implementation proved to be time consuming due to differences in equipment and the need for characterization. This paper reports a simple and easy protocol combining a second extended oxygen plasma treatments and proper storage to produce usable hydrophilicPDMSdevices. The results show that at a plasma power of 70 W, an extended treatment of over 5 min would allow the PDMSsurface to remain hydrophilic for more than 6 h. Storing the treatedPDMSdevices in de-ionized water would allow them to maintain their hydrophilicity for weeks. Atomic force microscopy alysis shows that a longer oxygen plasma time produces a smoother surface.